components/camel-jcache/src/main/java/org/apache/camel/component/jcache/JCacheHelper.java

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.camel.component.jcache;

import java.lang.reflect.Constructor;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

import org.apache.camel.RuntimeCamelException;

public final class JCacheHelper {
    private JCacheHelper() {
    }

    public static <K, V> JCacheManager<K, V> createManager(JCacheConfiguration configuration) {
        if (isOSGi()) {
            try {
                Class<?> type = Class.forName("org.apache.camel.component.jcache.osgi.OSGiCacheManager");
                Constructor<?> ctor = type.getConstructor(JCacheConfiguration.class);

                return (JCacheManager<K, V>)ctor.newInstance(configuration);
            } catch (Exception e) {
                throw new RuntimeCamelException(e);
            }
        }

        return new JCacheManager<>(configuration);
    }

    @SuppressWarnings("uncheked")
    public static <T> T tcclProxy(final T instance, Class<T> type, final ClassLoader classLoader) {
        return (T) Proxy.newProxyInstance(
            JCacheHelper.class.getClassLoader(),
            new Class<?>[] {
                type
            },
            (Object proxy, Method method, Object[] args) -> {
                final ClassLoader tccl = Thread.currentThread().getContextClassLoader();
                try {
                    Thread.currentThread().setContextClassLoader(classLoader);
                    return method.invoke(instance, args);
                } finally {
                    Thread.currentThread().setContextClassLoader(tccl);
                }
            }
        );
    }

    public static boolean isOSGi() {
        try {
            // Check if we are in an osgi container
            Class<?> fu = Class.forName("org.osgi.framework.FrameworkUtil");
            if (fu != null) {
                Method method = fu.getMethod("getBundle", Class.class);
                if (method != null) {
                    return method.invoke(null, JCacheHelper.class) != null;
                }
            }
        } catch (ClassNotFoundException e) {
        } catch (Exception e) {
            throw new RuntimeCamelException(e);
        }

        return false;
    }
}